Efficacy of Antidepressants in Irritable Bowel Syndrome

Abstract

Purpose: This study was performed to inform the American College of Gastroenterology monograph on irritable bowel syndrome (IBS). IBS is a chronic functional gastrointestinal disorder with a relapsing and remitting course. Current evidence for treatment of IBS with antidepressants is limited. We conducted a systematic review to estimate efficacy of antidepressants in the treatment of IBS. Methods: MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to April 2008) to identify randomized controlled trials (RCTs) comparing antidepressants with placebo in adult IBS patients. A diagnosis of IBS could be based on either clinical impression or symptom-based diagnostic criteria, combined with the results of investigations to exclude organic disease. Subjects were required to be followed up for at least 1 week, and studies had to report either a global assessment of IBS symptom cure or improvement, or abdominal pain cure or improvement, after completion of therapy. Data were extracted as intention-to-treat analyses with drop-outs assumed to be treatment failures. Symptom data were pooled using a random effects model, and effect of antidepressants compared to placebo was reported as the relative risk (RR) of remaining symptomatic, with a 95% confidence interval (CI). The number needed to treat (NNT) and 95% CIs were calculated from the reciprocal of the risk difference from the meta-analysis. Results: 13 RCTs were eligible for inclusion, including 789 patients, 432 of whom received antidepressants and 357 placebo. 8 RCTs used tricyclic antidepressants (TCAs), 4 RCTs selective serotonin reuptake inhibitors (SSRIs), and 1 RCT both. There were 182 of 432 (42.1%) patients assigned to antidepressant therapy with persistent or unimproved IBS symptoms following therapy, compared to 231 of 357 (64.7%) allocated to placebo. The RR of IBS symptoms persisting after treatment with antidepressants versus placebo was 0.66 (95% CI 0.57 to 0.78). The NNT with antidepressants was 4 (95% CI 3 to 6). 9 RCTs compared TCAs to placebo in 575 patients. Of the 319 patients receiving TCAs, 132 (41.4%) had persistent symptoms after treatment, compared to 153 of 256 (59.8%) receiving placebo (RR of IBS symptoms persisting = 0.68; 95% CI 0.56 to 0.83). The NNT with TCAs was 4 (95% CI 3 to 8). 5 RCTs compared SSRIs with placebo in a total of 230 patients. There were 50 of 113 (44.2%) patients allocated to SSRIs with persistent symptoms following therapy, compared to 83 of 117 (70.9%) placebo patients. The RR of IBS symptoms persisting with SSRIs compared to placebo was 0.62 (95% CI 0.45 to 0.87), and the NNT was 3.5 (95% CI 2 to 14). Conclusion: Antidepressants are effective in the treatment of IBS.